Network Working Group B. Stewart, Editor
Request for Comments: 1318 Xyplex, Inc.
April 1992
Definitions of Managed Objectsfor Parallel-printer-like Hardware Devices
Status of this Memo
This document specifies an IAB standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "IAB
Official Protocol Standards" for the standardization state and status
of this protocol. Distribution of this memo is unlimited.
1. Abstract
This memo defines a portion of the Management Information Base (MIB)
for use with network management protocols in TCP/IP based internets.
In particular, it defines objects for the management of
parallel-printer-like devices.
2. The Network Management Framework
The Internet-standard Network Management Framework consists
of three components. They are:
RFC 1155 which defines the SMI, the mechanisms used for
describing and naming objects for the purpose of management.
RFC 1212 defines a more concise description mechanism, which
is wholly consistent with the SMI.
RFC 1156 which defines MIB-I, the core set of managed
objects for the Internet suite of protocols. RFC 1213,
defines MIB-II, an evolution of MIB-I based on
implementation experience and new operational requirements.
RFC 1157 which defines the SNMP, the protocol used for
network access to managed objects.
The Framework permits new objects to be defined for the
purpose of experimentation and evaluation.
3. Objects
Managed objects are accessed via a virtual information
store, termed the Management Information Base or MIB.
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RFC 1318 PARALLEL-PRINTER-LIKE-MIB April 1992
Objects in the MIB are defined using the subset of Abstract
Syntax Notation One (ASN.1) [7] defined in the SMI. In
particular, each object has a name, a syntax, and an
encoding. The name is an object identifier, an
administratively assigned name, which specifies an object
type.
The object type together with an object instance serves to
uniquely identify a specific instantiation of the object.
For human convenience, we often use a textual string, termed
the OBJECT DESCRIPTOR, to also refer to the object type.
The syntax of an object type defines the abstract data
structure corresponding to that object type. The ASN.1
language is used for this purpose. However, the SMI [3]
purposely restricts the ASN.1 constructs which may be used.
These restrictions are explicitly made for simplicity.
The encoding of an object type is simply how that object
type is represented using the object type's syntax.
Implicitly tied to the notion of an object type's syntax and
encoding is how the object type is represented when being
transmitted on the network.
The SMI specifies the use of the basic encoding rules of
ASN.1 [8], subject to the additional requirements imposed by
the SNMP.
3.1. Format of DefinitionsSection 5 contains the specification of all object types
contained in this MIB module. The object types are defined
using the conventions defined in the SMI, as amended by the
extensions specified in [9,10].
4. Overview
The Parallel-printer-like Hardware Device MIB applies to
interface ports that might logically support the Interface
MIB, a Transmission MIB, or the Character MIB (most likely
the latter). The most common example is a Centronics or
Data Products type parallel printer port.
The Parallel-printer-like MIB is one of a set of MIBs
designed for complementary use. At this writing, the set
comprises:
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RFC 1318 PARALLEL-PRINTER-LIKE-MIB April 1992
Character MIB
PPP MIB
RS-232-like MIB
Parallel-printer-like MIB
The RS-232-like MIB and the Parallel-printer-like MIB
represent the physical layer, providing service to higher
layers such as the Character MIB or PPP MIB. Further MIBs
may appear above these.
The following diagram shows two possible "MIB stacks", each
using the RS-232-like MIB.
.-----------------.
.-----------------. | Standard MIB |
| Telnet MIB | | Interface Group |
|-----------------| |-----------------|
| Character MIB | | PPP MIB |
|-----------------| |-----------------|
| RS-232-like MIB | | RS-232-like MIB |
`-----------------' `-----------------'
The intent of the model is for the physical-level MIBs to
represent the lowest level, regardless of the higher level
that may be using it. In turn, separate higher level MIBs
represent specific applications, such as a terminal (the
Character MIB) or a network connection (the PPP MIB).
The Parallel-printer-like MIB is mandatory for all systems
that have such a hardware port supporting services managed
through some other MIB, for example, the Character MIB.
The Parallel-printer-like MIB includes multiple similar
types of hardware, and as a result contains objects not
applicable to all of those types. Such objects are in a
separate branch of the MIB, which is required when
applicable and otherwise absent.
The Parallel-printer-like MIB includes Centronics, Data
Products, and other parallel physical links with a similar
set of control signals.
The MIB contains objects that relate to physical layer
connections. Such connections may provide interesting
hardware signals (other than for basic data transfer), such
as Power and PaperOut.
The MIB comprises one base object and three tables, detailed
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RFC 1318 PARALLEL-PRINTER-LIKE-MIB April 1992
in the following sections. The tables contain objects for
ports and input and output control signals.
5. DefinitionsRFC1318-MIB DEFINITIONS ::= BEGIN
IMPORTS
Counter
FROM RFC1155-SMI
transmission
FROM RFC1213-MIB
OBJECT-TYPE
FROM RFC-1212;
-- this is the MIB module for Parallel-printer-like
-- hardware devices
para OBJECT IDENTIFIER ::= { transmission 34 }
-- the generic Parallel-printer-like group
-- Implementation of this group is mandatory for all
-- systems that have Parallel-printer-like hardware
-- ports supporting higher level services such as
-- character streams
paraNumber OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of ports (regardless of their current
state) in the Parallel-printer-like port table."
::= { para 1 }
-- the Parallel-printer-like Port table
paraPortTable OBJECT-TYPE
SYNTAX SEQUENCE OF ParaPortEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"A list of port entries. The number of entries is
given by the value of paraNumber."
::= { para 2 }
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